The invention relates to a display device comprising a plurality of pixels arranged in the form of a matrix in rows and columns, with a liquid crystal material from the group of smectic liquid crystal materials comprising ferroelectric liquid crystal material having a deformable helix, ferroelectric liquid crystal material having a twisted smectic structure, monostable ferroelectric liquid crystal material, electroclinic smectic A liquid crystal material and antiferroelectric liquid crystal material between a first substrate and a second substrate, and further comprising a group of row electrodes and a group of column electrodes, each pixel on at least one substrate comprising a picture electrode which is connected to a column electrode or row electrode via an active switching element, the display device comprising means for presenting selection voltages to the row electrodes and data voltages to the column electrodes.
Display devices of this type are applicable as video displays (for example, in projection systems) but also, for example, in datagraphic monitors, or as viewfinders.
A display device of the type mentioned above is described in "A Full-Color DHF-AMLCD with Wide Viewing Angle" in SID 94 Digest, pp. 430-433. The use of devices with DHFLC material (Deformed Helix Ferroelectric Liquid Crystal) is described in this article as being advantageous with respect to SSFLC devices (Surface Stabilized Ferroelectric Liquid Crystal) due to the lack of multidomains, while grey scales can be better realized due to a more continuous change of the transmission/voltage characteristic. In spite of the fast switching time which is mentioned for the mixture used in the display device, the frame frequency remains, however, too low for video applications (NTSC or PAL). Moreover, image sticking (after images) also occurs in the device described in this article.